1. Field of the Invention
The present invention relates to a frequency hopping wireless communication system and a frequency hopping wireless communication apparatus which can simultaneously communicate different data such as data like a voice that is communicated by a communication frame of a fixed length, data like a packet that is communicated by a communication frame of a variable length, and the like.
2. Related Background Art
Hitherto, there is a wireless communication apparatus using a frequency hopping system because of a reason such that it is hardly influenced by a fading, an interfering wave, or the like due to a multiple-path.
According to the frequency hopping system, a communication is performed while switching a frequency in a certain frequency band every communication frame. There are the following two methods: a method whereby for an apparatus having a predetermined transmission speed as in a public line, a communication is executed by using a communication frame of a fixed length according to the transmission speed; and a method whereby a length of communication frame is varied in accordance with an amount of data to be transmitted as in a packet communication.
In the case where a terminal which can perform a communication through a public line and a terminal which can perform a packet communication between the terminals without intervening the public line exist in one system, the case where one terminal has both of a function for performing a communication through the public line and a function for performing a packet communication, or the like, there is a situation such that both of a communication frame of a fixed length and a communication frame of a variable length are simultaneously used.
However, when the communication frame of a fixed length and the communication frame of a variable length or communication frames of a plurality of variable lengths are simultaneously used, since the lengths of the communication frames are different, the communications cannot be synchronized, so that a data error occurs due to a collision of data or a mutual interference.
When the data error occurs, data having a non-real-time performance like packet data can be again transmitted. However, when a data error frequently occurs, a transmission speed remarkably deteriorates and in case of data such as a voice or the like having a strong real-time performance, it is difficult to perform an error control due to the retransmission, so that such data becomes noises. Therefore, the communication by the frequency hopping system using the communication frame of the fixed length and the communication by the frequency hopping system using the communication frame of the variable length cannot be simultaneously executed by the same system or same terminal.